Projection tube with electrically movable target electrode



Oct. 19, 1954 v. TRAD 2,692,346

PROJECTION TUBE WITH ELECTRICALLY MOVABLE TARGET ELECTRODE Original Filed March l5, 1952 l/Zs I/ JNVENToR. "gv-f f l//cToR TRAD ATTORNEY Patented Oct. 19, 1954 STATS ATENT OFFICE PROJECTION TUBE WITH ELECTRICALLY MOVABLE TARGET ELECTRODE Victor rllrad, Asbury Park, N. J.

7 Claims.

This invention relates to a television projection tube such as may be used for the purpose of displaying images upon a large television screen.

This application is a divisional of patent application Serial No. 276,756, filed March l5, 1952, entitled: Projection Tube with Movable Target Electrode and issued May 5, 1953, as Patent No. 2,637,829.

An object of the present invention is to provide a television projection tube having a builtin optical system, together with a method of mechanically focusing said tube for different projection throws, by means of small electrical motors sealed within the tube envelope.

The invention consists of the construction, combination and arrangement of parts, as herein illustrated, described and claimed,

in the accompanying drawings, forming a part hereof, is illustrated one embodiment of the invention, in which drawings similar reference characters designate corresponding parts, and in which:

Figure l. is a somewhat diagrammatic view in front elevation of a projection tube, in accordance with the present invention.

Figure 2 is a fragmentary view in side elevation, somewhat enlarged, of the tube focusing device, as shown in Figure l.

Figure 3 is a longitudinal section of a projection tube having attached thereto a focusing device, somewhat enlarged .for the sake of clarity, according to this invention.

Referring to the drawings, l d indicates a sealed glass envelope, such as may be used in connection with a cathode ray tube. An ion gun Il, such as is carried in the rear of such tube Hl, is directed at 'the face thereof. The front i2 oi the tube le comprises a ilat transparent surface at the center oi which there is carried the focusing device, generally indicated at it. rThe focusing device i3 is adapted to move a phosphorcoated face plate lli, as hereinafter set forth.

Between the face plate ifi and the ion gun l l, there is provided the well known anode ring l5. The rear surface lt of the envelope I9 is polished and mirrored, and optically ground to provide the curved reflecting surface of the well known Schmidt optical system. inasmuch as this surface is contained Within the vacuum of the tube I0, the necessity for cleaning the surface is thereby eliminated. When the tube is in operation, electrons from the ion gun l! strike the phosphor-coated face plate ld, forming an image upon the said plate. ln the present embodiment of the invention, the image is taken from the striking side of the face plate ill, and projected upon the mirrored surface at the rear oi the tube.

In order to adapt the tube for use over a variety of focal distances, it is necessary to provide some means for changing the position of the face plate lli. Accordingly, a bracket Il is secured to the inner surface of the face l2 of the tube l. rfhe bracket il is adapted to hold, in a manner hereinafter described, the face plate lll. The face plate thus held may be adjusted vertically, laterally, and longitudinally.

The motion imparted to the face plate It stems from the operation oi three small motors le, i9 and 2li, located within the envelope of the tube lll. Motors i9 and Ztl are provided with Worms 2l, secured to the shafts thereof, which worms engage a face plate support member 22. By energizing the motors I9 and 2i! there may be imparted to the support 22 a suitable motion across the front of the plate i2 of the tube it, in any direction. The face plate supporting bracket ll carries at the center thereof a worm 23, which worm is threadably engaged with the face palte it, as shown in Figure 2. The motor i8 is adapted to drive a small gear 2li, which is in mesh with a larger gear 25, coupled to the worm 23, by means of a key 25.

A pin 2l is inserted within a suitable opening 28 in the rear of the face plate lli, to prevent said face plate from rotating when the motor i8 turns the gears 2li and 25, thereby causing the worm 23 to enter or leave the back of the plate it, as the case may be.

Knobs 29 and 39, shown on the outside of the face plate E2 in Figure 2, are connected to switches 5l and 32, which switches in turn activate the motors I8, i9, 2li, respectively. The motors i3, i9, 2t! are supplied with current from a suitable source (not shown) by means of leads 33 which traverse the front plate l2, and are sealed therein so as not to interfere with the vacuum of the tube lil.

From the foregoing, it will be seen that all of the necessary motions requisite to focus and orient the image coming from the ion gun il, may be provided by the manipulation of the knobs 2S and Sil, located on the outside of the tube lil.

Having thus fully described the invention, what is claimed as new, and desired to be secured by Letters Patent of the United States, is:

1. A television image projection tube comprising, a sealed envelope, a transparent front wall on said envelope, a rear wall, an ion gun carried by the rear wall of the envelope so that its ion stream is directed toward the front wall, a faceplate movably held within the envelope to receive and translate the ion stream into an image, a reflecting surface upon the rear wall adapted to receive and transmit the image from the faceplate, a source of electrical potential, switch means connected to the electrical potential source, motors, carried within the envelope and connected to the switch means, said motors being mechanically coupled to the faceplate whereby the position of the faceplate within the tube may be changed so as to focus and orient the image without disturbing the seal of the said tube.

2. A television image projection tube comprising, a sealed envelope, a transparent front wall on said envelope, a rear wall, an ion gun carried by the rear wall of the envelope so that its ion stream is directed toward the front wall, a faceplate, a worm threadably inserted into the face plate, said worm being movably held within the envelope, said faceplate being constructed so as to receive and translate the ion stream into an image, a reflecting surface upon the rear wall adapted to receive and transmit the image from the faceplate, a source of electrical potential, switch means connected to the electrical potential source, motors, carried within the envelope and connected to the switch means, said motors being mechanically coupled to the faceplate whereby the position of the faceplate within the tube may be changed so as to focus and orient the image without disturbing the seal of the said tube.

3. A television image projection tube comprising, a sealed envelope, a transparent front wall on said envelope, a rear wall, an ion gun carried by the rear wall of the envelope so that its ion stream is directed toward the front wall, a faceplate movably held within the envelope to receive and translate the ion stream into an image, a reflecting surface upon the rear wall adapted to receive and transmit the image from the faceplate, a source of electrical potential, switch means connected to the electrical potential source, motors, carried within the envelope and connected to the switch means, said motors being mechanically coupled to the faceplate by a bracket whereby the position of the faceplate within the tube may be changed so as to focus and orient the image without disturbing the seal of the said tube.

e. A television image projection tube comprising, a sealed envelope, a transparent front wall on said envelope, a rear wall, an ion gun carried by the rear wall of the envelope so that its ion stream is directed toward the front wall, a faceplate movably held within the envelope to receive and translate the ion stream into an image, a reflecting surface upon the rear wall adapted to receive and transmit the image from the faceplate, a source of electrical potential, switch means connected to the electrical potential source, control knobs carried upon the outside face of the front .vall to operate the switch means, motors, carried within the envelope and connected to the switch means, said motors being mechanically coupled to the faceplate whereby the position of the faceplate within the tube may be changed so as to focus and orient the 4 image without disturbing the seal of the said tube.

5. A television image projection tube comprising, a sealed envelope, a transparent front Wall on said envelope, a rear wall, an ion gun carried by the rear wall of the envelope so that its ion stream is directed toward the front wall, a faceplate movably held within the envelope to receive and translate the ion stream into an image, a reflecting surface upon the rear Wall adapted to receive and transmit the image from the faceplate, a source of electrical potential, switch means secured to the outside face of the front Wall connected to the electrical potential source, motors, carried within the envelope and connected to the switch means, said motors being mechanically coupled to the faceplate whereby the position of the faceplate within the tube may be changed so as to focus and orient the image without disturbing the seal of the said tube.

6. A television image projection tube comprising, a sealed envelope, a transparent front wall on said envelope, a rear Wall, an ion gun carried by the rear wall of the envelope so that its ion stream is directed toward the front wall, a faceplate, a worm threadably inserted into the faceplate, said worm being movably held within the envelope, said faceplate being constructed so as to receive and translate the ion stream into an image, a reflecting surface upon the rear Wall adapted to receive and transmit the image from the faceplate, a source of electrical potential, switch means connected to the electrical potential source, control knobs carried upon the outside of the front wall to operate the switch means, motors, carried within the envelope and connected to the switch means, said motors being mechanically coupled to the faceplate by a bracket whereby the position of the faceplate within the tube may be changed so as to focus and orient the image without disturbing the seal of the said tube.

7. A television image projection tube comprising, a sealed envelope, a transparent front Wall on said envelope, a rear wall, an ion gun carried by the rear wall of the envelope so that its ion stream is directed toward the front wall, a faceplate movably held within the envelope to receive and translate the ion stream into an image, a reflecting surface upon the rear wall adapted to receive and transmit the image from the faceplate, a source of electrical potential, switch means connected to the electrical potential source, motors, carried within the envelope and connected to the switch means by leads sealed within the wall of the tube, said motors being mechanically coupled to the faceplate whereby the position of the faceplate within the tube may be changed so as to focus and orient the image without disturbing the seal of the said tube.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,267,769 Ardenne Dec. 30, 1941 2,403,996 Potter July 16, 1946 2,435,316 Larson Feb. 3, 1948 2,440,735 Cawein May 4, 1948 2,520,190 Amdursky Aug. 29, 1950 

